How are mitochondrial fusion and fission regulated?

Mitochondrial fusion and division are regulated by large GTPases. Mitofusins are involved in the fusion of the outer mitochondrial membrane, while OPA1/Mgm1 facilitates fusion of the inner mitochondrial membrane. Drp1/Dnm1 plays a vital role in mitochondrial division. Various other proteins also influence the activities of these proteins in different cellular environments. Additionally, phosphorylation, ubiquitination, sumoylation and other modifications of fusion and fission proteins regulate their function. Lastly, Calcium (Ca2+) serves as a signaling molecule that controls mitochondrial fission in different cell types. The improper regulation of mitochondrial fusion or division is linked to several genetic neurodegenerative diseases in humans.